BMW R25 1955 (Semarang) For Sale. With the 1953-to-1956 R25/3, BMW updated the 250cc OHV single with a new hydraulic fork, a gas tank that was flatter and longer, with the tool box moved to the side, and different wheels and hubs. Rims were changed from steel to alloy, and shrank to 18” from 19”. Engine configuration specifications changed slightly. The compression ratio went from 6.5:1 to 7.0:1,
